The present invention relates to an apparatus useful for separating liquids and/or solids from a geothermal water vapor stream.
The removal of denser material from a moving vapor stream is desirable in many applications such as removing various liquid droplets and entrained solids from water vapor. Specifically, it is highly desirable to remove liquid droplets and entrained solids from a vapor stream which is used in the steam generation of electricity. Liquid droplets and entrained solids in the vapor stream can cause wear, scaling, and corrosion of the turbine blades, nozzles, and other turbine components of the steam-generation facility. This problem of wear, scaling, and corrosion of turbine components is especially apparent in geothermal steam generation where water droplets, present in the vapor due to the presence of water in the subterranean formation or the result of injecting water into the subterranean formation, dissolve and carry various minerals present in the formation in the vapor stream. These dissolve and minerals may deposit upon the turbine and within valves of the electrical generation apparatus, adding to the corrosion, scaling, and wear of the apparatus, which may eventually lead to blockage of the various turbine components.
Geothermally produced vapor may consist of from about 5 to 10,000 times more dissolved solids than vapor produced by other heating methods. In order to lessen to damage resulting from corrosion, scaling, and wear of turbine components of the steam-generating apparatus, it is beneficial to separate out about 90 percent of the solids, such as minerals, dissolved or carried by the geothermal vapor.
Previously used separators are rather large devices into which a vapor stream is diverted to remove liquid droplets and dissolved or carried solids. Examples of these types of devices are shown in U.S. Pat. Nos. 4,445,472 and 3,251,176.
A major disadvantage of these types of separating devices is that, as a vapor stream leaves the pipeline and enters into the larger vessel, a transitional turbulence is created which causes shearing and reduction of number and size of the liquid droplets. As the liquid droplets decrease in number and size, the efficiency of removing the particles decreases. Thus, the very use of these types of separators increases the potential that liquid droplets and entrained impurities will enter a steam-generation facility. Furthermore, as the quantity of liquid droplets decreases, the entrained solids concentrate in the remaining droplets, increasing the potential of these solids to come out of solution and deposit upon the turbine components.
In typical geothermal operations, it is desirable to use more than one and usually different types of separating devices for each feed pipeline, because of the need to remove a sufficient amount of liquid droplets and entrained solids from the vapor in order to minimize corrosion and wear. The increased number of separators intensifies the turbulence, resulting in increased shearing and reduction of the quantity and size of the liquid droplets, and thus the loss of efficiency of removal of the liquid droplets and entrained solids.
In conjunction with the larger separator, some smaller in-line separators may be used to assist in the removal of liquid droplets and entrained solids. The small in-line separators are used to reduce the cost of removing liquid droplets and entrained solids from the vapor, but are inefficient in and of themselves and cannot be used independently to remove a sufficient amount of the liquid droplets and entrained solids to minimize corrosion and wear.